This invention relates to a sunroof of motor vehicles, and more particularly to an opening and closing mechanism for such a sunroof.
Heretofore, a link means, a screw means or the like has been used in the mechanism for opening and closing a sunroof of motor vehicles, which has one edge pivotably connected to the vehicular roof. The mechanism of this kind has a large size and a complicated construction, and therefore it is difficult to house such mechanism in a narrow space at the rear of a trim plate. In addition, the load induced at the start of opening is large and smoothness of the operation can not be obtained sufficiently.
As an improved device, there has been proposed a roof panel opening and closing mechanism which is composed of shoes pulled by cables to move forward and backward along guide rails on both sides of an opening formed in the roof, a lever pivotably connected to each of the shoes, an arm integral with the lever, pins mounted at both free ends of the arm and the lever, a cam member having a cam groove with which the pin of the arm is engaged, a bracket fixed to the under surface of the roof panel and having a long hole with which the pin of the lever is engaged, a drive gear in mesh with the cables, and other parts. This invention is related to an improvement of such roof panel opening and closing mechanism, which employs shoes moving forward and backward along guide rails.
In such an opening and closing mechanism mentioned above, pins are erected at positions respectively corresponding to three apexes of a triangular lift link (composed of the lever and the arm). The first pin at one end of the lift link is engaged with a guide groove in the bracket fixed to the roof panel, while the second pin at the other end thereof is engaged with an inclined groove in the stationary guide. And the remaining third pin positioned between those two pins is pivotally connected to the shoe. When the shoe is driven in one direction, the lift link moves in the same direction as the shoe and at the same time, the second pin descends along the inclined groove. When this happens, the lift link is rotated in one direction so that the first pin pushes up the bracket in the panel opening direction. Meanwhile, when the shoe is driven in the other direction, the lift link moves in the same direction as the shoe and at the same time, the second pin ascends along the inclined groove. When this happens, the lift link is rotated in the other direction so that the first pin lowers the bracket in the panel closing direction. Since the inclined groove has a linear form, the moving speed of the panel in the opening and closing directions is substantially in proportion to that of the shoe. In other words, the extent of movement of the panel in the opening and closing stroke is substantially in proportion to the extent of movement of the shoe. As a result, in such a construction where a seal member is fitted over the edge of the panel and the opening is closed up tightly upon closing of the panel, a relatively large force is required when opening the panel from the closed-up state as well as when closing the panel into the closed-up state after the seal member has come into contact with the edge of the opening. In the process of turning a handle to close the panel, therefore, one unfamiliar with the operation of such a mechanism often believes that the panel has been closed completely when the handle becomes hard to turn. In this state, however, the panel is not yet closed up into the air-tight state. To the contrary, when opening the panel from the closed-up state, the handle is hard to turn at the beginning and then becomes easy to turn abruptly after it has been turned to some degree. Thus, the mechanism can not be operated smoothly.